When Harry Anderson (1906-1996) set out to illustrate images from his 7th Day Adventist religious faith, he turned to photo reference to give him added realism.
Here are the photos next to the finished paintings. It's interesting to compare the changes he made as he went from the reference to the painting.
Here, Jesus is lowered from heaven to outreached human hands. The painting invents the sweep of the garment, and the warm reflected light from the back of the figure to the encircling white fabric.
This is one of Anderson's most famous religious paintings. Much of the spontaneous action and accurate eyelines came from posing the whole grouping together and actually having them walk.
Norman Rockwell didn't shoot reference this way, and would instead generally pose models separately and would set up walking poses somewhat artificially.
The potential pitfall of shooting photo reference, especially for religious paintings, is that one can get caught up in the commonplace and random details of the photo and lose sight of the mental image of the scene.
Anderson certainly didn't copy the reference, instead redrawing it, and controlling the values. Note how he downplayed the reflected light on the shadow side of the chest.
Like many other illustrators of his day, Anderson used black and white photos, not wanting to be influenced by the colors. He spared no expense or effort to get good scrap. According to his biography, a large percentage of his commission went to model expenses and photography fees.
Most of the photos he used he took and developed himself in a bedroom that he converted into a photo studio and darkroom. He used professional models—who even 50 years ago charged as much as sixty dollars an hour—but he also used neighbors and friends.
The biography says: "By posing his models in approximately the right costume and photographing them, Harry could obtain what he needed—the proper foreshortening of limbs, inclination of head, relationship of light and shadow."
Illustrated bio in book form (emphasis on religious work): Harry Anderson: The Man Behind the Paintings